大豆根腐病菌拮抗细菌筛选及抗生作用

SCREENING OF ANTAGONISTIC BACTERIA AGAINST PATHOGENIC FUNGUS OF SOYBEAN ROOT ROT AND THEIR BIOCONTROL EFFICIENCY

从大豆根际土壤中分离纯化得到 388个细菌菌株 ,从中筛选对大豆根腐病病原尖孢镰刀菌 (Fusariumoxysporum )、茄腐镰刀菌 (Fusariumsolani)和立枯丝核菌 (Rhizoctoniasolani )有拮抗作用的菌株 ,采用无菌室内点接法初筛 ,抑菌带大于 2 0mm以上的有 12株 ,通过盆栽防效试验 ,进一步证明 12个菌株中有 6个菌株盆栽防治尖孢镰刀菌和立枯丝核菌达到 4 6 .0 % - 78.5 %。菌株与病原真菌共培养结果显示 ,菌株B2、B5 7、B85和B6 9使尖孢镰刀菌菌丝干重分别减少 5 1.2 7%、4 0 .78%、38.87%和 34.5 8% ;菌株B5 7使茄腐镰刀菌菌丝干重减少 71.4 8%。菌株分泌物对病原真菌的拮抗作用研究结果表明 ,B5 7的分泌物对尖孢镰刀菌抑制率最高 ,3d为 82 .1% ,6d为 90 .6 % ;其次是B16 ,3d为 5 8.8% ,6d为 5 1.1%。

Three hundred and eighty eight bacterial strains were isolated from soybean rhizosphere soil. Twelve bacterial strains were screened by the inhibition zone method ,which had better efficacy against the major causal agents: Fusarium oxysporum,Fusarium solani,Rhizoctonia solani. In potted trial, 6 strains showed some efficacy against pathogenic fungus of soybean root rot. The dry weights of Fusarium oxysporum,Fusarium solani were reduced 40.78% and 71.48% respectively with which the strain B57 was cocultured in King's broth(KB) liquid medium. The radius of pathogenic fungi(Fusarium oxysporum) was reduced respectively 82.1% in 3d and 90.6% in 6d by the diffusion of strain B57 compared with that of the control . In general, the tests in vitro and in vivo showed that strain B57 had the best biological control efficacy against pathogens of soybean root rot.